TW202415722A - Thermoplastic resin composition, method of preparing the same, and molded article including the same - Google Patents

Abstract

The present invention relates to a thermoplastic resin composition, a method of preparing the same, and a molded article including the same. According to the present invention, the present invention has an effect of providing a thermoplastic resin composition having fluidity and weather resistance equal or superior to those of conventional ASA resins and being capable of imparting excellent appearance by suppressing occurrence of flow marks and a molded article including the thermoplastic resin composition.

Description

Thermoplastic resin composition, method for preparing the same, and molded article containing the same

The present invention relates to a thermoplastic resin composition, a method for preparing the same, and a molded article containing the same, and more particularly, to a thermoplastic resin composition having excellent fluidity and weather resistance and being able to impart excellent appearance by suppressing the occurrence of flow marks, a method for preparing the same, and a molded article containing the same.

Acrylate-styrene-acrylonitrile graft copolymer (hereinafter referred to as "ASA resin") has good weather resistance, aging resistance, chemical resistance, and processability, and is used in various fields such as automobiles, leisure products, building materials, and gardening sundries.

In recent years, consumers' preference for molded articles with excellent dyeability has increased significantly in consideration of aesthetic design. However, when a product having a desired shape is manufactured by injection molding a conventional ASA resin, appearance defects such as flow marks occur. Therefore, there is an increasing demand for an ASA resin that can solve these problems (i.e., can impart an excellent appearance).

Flow marks refer to the streak-like appearance defects that appear during the molding process due to the uneven flow of the resin composition in the mold.

The shapes of flow marks that appear in injection molding include irregular thickness, vinyl record, and wavy stripes such as tiger stripes. Specifically, in the case of ASA injection molded objects, when the molten resin cools, gaps will be generated on the mold surface due to the difference in the solidification rate of the resin composition. In addition, when the fluidity of the resin composition is unstable, flow marks in the form of repeated wavy stripes will appear due to the difference in transfer on the surface in contact with the mold.

Generally, the method of increasing the injection temperature and speed is used to suppress the appearance of flow marks. However, this method is difficult to apply due to the inconsistency of injection conditions. In addition, the method of optimizing the gate thickness and position is also used. However, this method is difficult to apply due to the inconsistency of mold design.

In addition, there is also a method of improving the flow properties of ASA resin by adding internal lubricants and external lubricants to ASA resin. However, when using the above method, it is difficult to obtain a transparency improvement effect, and low molecular weight substances including lubricants will evaporate and deposit in the mold during the injection molding process. [Related technical documents] [Patent documents] KR 2022-0000554 A

[Technical issues]

Therefore, the present invention has been completed in view of the above problems, and one object of the present invention is to provide a thermoplastic resin composition having excellent fluidity and weather resistance and capable of imparting excellent appearance by preventing deterioration of surface properties that may occur during molding processing.

Another object of the present invention is to provide a molded object made using the thermoplastic resin composition.

The above and other objects can be achieved by the present invention described below.

[Technical Solution] I) According to one aspect of the present invention, a thermoplastic resin composition is provided, which comprises 100 parts by weight of a base resin, wherein the base resin comprises an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) containing an acrylate rubber having an average particle size of 400 to 600 nm, an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) containing an acrylate rubber having an average particle size of 30 to 200 nm, a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and an aromatic vinyl compound-vinyl cyanide compound copolymer (C) having a weight average molecular weight of 50,000 to 70,000 g/mol; and 0.5 to 4 parts by weight of a polyol having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol. g/mol of an aromatic vinyl compound-vinyl cyanide compound copolymer (D). II) According to I), when the weights of (A-1), (A-2), (B), and (C) are a, b, c, and d, respectively, a, b, c, and d may satisfy the following equation 1: [Equation 1] a≤d＜b≤c, wherein a is an integer of 5 to 20, b is an integer of 26 to 35, c is an integer of 35 to 60, and d is an integer of 6 to 25. III) According to I) or II), the base resin may contain (A-1), (A-2), (B), and (C) in a weight ratio of 1:2 to 3:4 to 5:1 to 2 ((A-1): (A-2): (B): (C)). IV) According to I) to III), the aromatic vinyl compound-vinyl cyanide compound copolymer (D) may have an intrinsic viscosity of 10 dL/g or more (IV, 25°C). V) According to I) to IV), the aromatic vinyl compound-vinyl cyanide compound copolymer (D) may have a bulk density of 0.1 to 0.5 g/ ^cm3 . VI) According to I) to V), the aromatic vinyl compound-vinyl cyanide compound copolymer (D) may have a weight average molecular weight greater than 1,000,000 g/mol. VII) According to I) to VI), the aromatic vinyl compound-vinyl cyanide compound copolymer (D) may contain 50 to 90% by weight of the aromatic vinyl compound and 10 to 50% by weight of the vinyl cyanide compound. VIII) According to I) to VII), the total amount of (A-1) and (A-2) may be 40% by weight or less based on 100% by weight of all components constituting the base resin. IX) According to I) to VIII), the heat-resistant resin (B) may contain 60 to 80% by weight of an α-methylstyrene-based monomer and 20 to 40% by weight of a vinyl cyanide compound. X) According to I) to IX), based on 100% by weight of the total acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1), the acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) may contain 40 to 60% by weight of the acrylate rubber, 25 to 45% by weight of the aromatic vinyl compound, and 5 to 20% by weight of the vinyl cyanide compound. XI) According to I) to X), based on 100% by weight of the total acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2), the acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) may contain 40 to 60% by weight of the acrylate rubber, 25 to 45% by weight of the aromatic vinyl compound, and 5 to 20% by weight of the vinyl cyanide compound. XII) According to I) to XI), the aromatic vinyl compound-vinyl cyanide compound copolymer (C) may contain 50 to 90% by weight of the aromatic vinyl compound and 10 to 50% by weight of the vinyl cyanide compound. XIII) According to another aspect of the present invention, a thermoplastic resin composition is provided, which comprises 100 parts by weight of a base resin, wherein the base resin comprises 5 to 20 parts by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) comprising an acrylate rubber having an average particle size of 400 to 600 nm, 20 to 40 parts by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) comprising an acrylate rubber having an average particle size of 30 to 200 nm, 30 to 60 parts by weight of a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and 5 to 30 parts by weight of a polyol having a weight average molecular weight of 50,000 to 70,000 g/mol. g/mol of an aromatic vinyl compound-vinyl cyanide compound copolymer (C); and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol, wherein the base resin comprises (A-1), (A-2), (B), and (C) in a weight ratio of 1:2 to 3:4 to 5:1 to 2 ((A-1): (A-2): (B): (C)). XIV) According to XIII), the thermoplastic resin composition may satisfy the following equation 3: [Equation 3] 380≤melt flow index×die expansion ratio×spiral×content of processing aid≤1,400, In equation 3, the melt flow index is a value measured for the thermoplastic resin composition at 220°C under a load of 10 kg according to ASTM D1238 (unit: g/10 min), the die expansion ratio is a value calculated by the following equation 4, and the spiral is a value obtained by using a spiral mold (2.0T) and an injection molding machine (Victory 80, Engel Co.) at 500°C. The length of the sample obtained by injection at an injection temperature of 300°C and a mold temperature of 80°C under a pressure of 100 kgf (unit: cm), and the content of the processing aid is the amount of the copolymer (D) (parts by weight) based on a total of 100 parts by weight of the base resin and the aromatic vinyl compound-vinyl cyanide compound copolymer. [Equation 4] Die expansion ratio = _Dex / _D0 , wherein _D0 is a die diameter of 2 mm, and _Dex is the diameter of the sample obtained by extrusion at 220°C under a load of 10 kg using a melt index tester (MI) having a die diameter ( _D0 ) of 2 mm (unit: mm). XV) According to XIII) to XIV), Equation 3 can satisfy the range of 400 to 1,300. XVI) According to XIII) to XV), the melt flow index may be 6.7 to 13.2 g/10 min. XVII) According to XIII) to XVI), the die expansion ratio may be 1.31 to 1.54. XVIII) According to XIII) to XVII), the spiral may be 21.1 to 24.4 cm. XIX) According to yet another aspect of the present invention, there is provided a method for preparing a thermoplastic resin composition, the method comprising kneading and extruding 100 parts by weight of a base resin at 200 to 300° C. and 100 to 500 rpm, the base resin comprising 5 to 20% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) comprising an acrylate rubber having an average particle size of 400 to 600 nm, 20 to 40% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) comprising an acrylate rubber having an average particle size of 30 to 200 nm, 30 to 60% by weight of a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and 5 to 30% by weight of a polyol having a weight average molecular weight of 50,000 to 70,000 g/mol. g/mol of an aromatic vinyl compound-vinyl cyanide compound copolymer (C); and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol, wherein the base resin comprises (A-1), (A-2), (B), and (C) in a weight ratio of 1:2 to 3:4 to 5:1 to 2 ((A-1): (A-2): (B): (C)). XX) According to another aspect of the present invention, a molded article comprising the above-mentioned thermoplastic resin composition is provided. [Advantageous Effects]

According to the present invention, there is provided a thermoplastic resin composition having flowability and weather resistance equivalent to or better than those of conventional ASA resins and capable of imparting excellent appearance by suppressing the occurrence of flow marks.

Specifically, the thermoplastic resin composition according to the present invention can be used for automobile exterior parts, and specific examples are side mirror housings, radiator grilles, or pillars.

Hereinafter, the thermoplastic resin composition of the present invention, the method for preparing the same, and the molded article containing the same will be described in detail.

The inventors of the present case have confirmed that when a graft copolymer containing two or more acrylic rubbers with different average particle sizes, heat-resistant resins, low molecular weight SAN resins, and ultra-high molecular weight SAN resins at a predetermined content ratio is used, the synergistic effect of these components can achieve excellent fluidity and weather resistance, and inhibit the occurrence of flow marks, thereby improving the appearance quality. Based on these results, the inventors of the present case conducted further research to complete the present invention.

The thermoplastic resin composition of the present invention is described in detail as follows.

The thermoplastic resin composition of the present invention comprises 100 parts by weight of a base resin, wherein the base resin comprises an acrylate-aromatic vinyl compound-vinyl cyanide graft copolymer (A-1) containing an acrylate rubber having an average particle size of 400 to 600 nm, an acrylate-aromatic vinyl compound-vinyl cyanide graft copolymer (A-2) containing an acrylate rubber having an average particle size of 30 to 200 nm, a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and an aromatic vinyl compound-vinyl cyanide copolymer (C) having a weight average molecular weight of 50,000 to 70,000 g/mol; and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol.

In this case, flowability and weather resistance equivalent to or better than those of conventional ASA resins can be achieved, and excellent appearance can be achieved by suppressing the occurrence of flow marks.

Hereinafter, the thermoplastic resin composition of the present invention will be described in detail with respect to each component. (A-1) Acrylate-aromatic vinyl compound-vinyl cyanide compound containing acrylic rubber having an average particle size of 400 to 600 nm

The acrylic rubber contained in the graft copolymer (A-1) may have an average particle size of 420 to 550 nm, preferably 450 to 520 nm, and more preferably 450 to 500 nm. Within this range, mechanical strength such as impact strength may be excellent.

In the present disclosure, the average particle size can be measured by dynamic light scattering, specifically, it can be measured as an intensity value using a Nicomp 380 particle size analyzer (manufacturer: PSS) in Gaussian mode. As a specific measurement example, a sample is prepared by diluting 0.1 g of latex (total solid content: 35 to 50 wt%) by 1,000 to 5,000 times with distilled water. Then, the average particle size of the sample is measured using a flow cell in an automatic dilution manner and in a dynamic light scattering/intensity 300 kHz/intensity-weight Gaussian analysis mode. At this time, the settings are as follows: temperature: 23°C; measurement wavelength: 632.8 nm; and channel width: 10 μsec.

For example, based on the total weight of the base resin, the content of the graft copolymer (A-1) can be 5 to 20% by weight, preferably 7 to 20% by weight, and more preferably 7 to 15% by weight. Within this range, fluidity and weather resistance equivalent to or better than those of conventional ASA resins can be achieved. In addition, due to the excellent die expansion ratio, the occurrence of flow marks can be suppressed and an excellent appearance can be achieved.

For example, the graft copolymer (A-1) may contain 40 to 60% by weight of an acrylic rubber, 25 to 45% by weight of an aromatic vinyl compound, and 5 to 20% by weight of a vinyl cyanide compound, preferably 45 to 55% by weight of an acrylic rubber, 30 to 40% by weight of an aromatic vinyl compound, and 10 to 15% by weight of a vinyl cyanide compound. Within this range, mechanical strength such as impact strength may be excellent.

In the present disclosure, a polymer comprising a compound means a polymer prepared by polymerizing the compound, and a unit in the polymer is derived from the compound.

In the present disclosure, for example, the alkyl acrylate compound may be an alkyl acrylate containing an alkyl group having 1 to 15 carbon atoms. Preferably, the alkyl acrylate compound may include one or more selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylbutyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, hexyl acrylate, heptyl acrylate, n-pentyl acrylate, and lauryl acrylate, preferably an alkyl acrylate containing an alkyl group having 1 to 4 carbon atoms, and more preferably butyl acrylate.

In the present disclosure, the aromatic vinyl compound may include, for example, one or more selected from the group consisting of styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, ethylstyrene, isobutylstyrene, tertiary butylstyrene, o-bromostyrene, p-bromostyrene, m-bromostyrene, o-chlorostyrene, p-chlorostyrene, m-chlorostyrene, vinyltoluene, vinylxylene, fluorostyrene, and vinylnaphthalene, preferably one or more selected from the group consisting of styrene and α-methylstyrene, and more preferably styrene. In this case, due to appropriate fluidity, processability and mechanical properties such as impact resistance may be excellent.

In the present disclosure, for example, the vinyl cyanide compound may include one or more selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and isopropylacrylonitrile, preferably acrylonitrile.

For example, the graft copolymer (A-1) can be prepared by emulsion polymerization. In this case, mechanical strength such as impact strength can be excellent.

In the present invention, an emulsion polymerization method commonly used in the field related to the present invention can be used without particular limitation. As a specific example, an emulsion graft polymerization method can be used. (A-2) Acrylate-aromatic vinyl compound-vinyl cyanide compound containing an acrylic rubber having an average particle size of 30 to 200 nm

For example, the acrylic rubber contained in the graft copolymer (A-2) may have an average particle size of 30 to 200 nm, preferably 50 to 180 nm, more preferably 70 to 150 nm, and even more preferably 70 to 120 nm. Within this range, excellent impact strength and gloss can be imparted to the finally prepared thermoplastic resin composition.

For example, based on the total weight of the base resin, the content of the graft copolymer (A-2) can be 26 to 35 wt%, preferably 28 to 35 wt%, and more preferably 28 to 33 wt%. Within this range, fluidity and weather resistance equivalent to or better than those of conventional ASA resins can be achieved. In addition, due to the excellent die expansion ratio, flow marks can be suppressed and excellent appearance can be achieved.

For example, the graft copolymer (A-2) may contain 40 to 60% by weight of an acrylate rubber, 25 to 45% by weight of an aromatic vinyl compound, and 5 to 20% by weight of a vinyl cyanide compound, preferably 45 to 55% by weight of an acrylate rubber, 30 to 40% by weight of an aromatic vinyl compound, and 10 to 15% by weight of a vinyl cyanide compound. Within this range, gloss and impact strength may be excellent.

For example, the graft copolymer (A-2) can be prepared by emulsion polymerization. In this case, the impact strength and gloss can be excellent.

In the present invention, the emulsion polymerization method commonly used in the field related to the present invention can be used without particular limitation. As a specific example, the emulsion graft polymerization method can be used.

The weight ratio of the graft copolymer (A-1) to the graft copolymer (A-2) (A-1:A-2) is preferably 1:2 or higher, more preferably 1:2 to 3, and even more preferably 1:2.5 to 1:3. Within this range, the fluidity and weather resistance can be maintained at a higher level, and the appearance can be improved by suppressing the occurrence of flow marks.

In the present disclosure, the weight ratio of A to B means the weight ratio of A:B.

Based on 100 wt% of all components constituting the base resin, the total amount of the graft copolymer (A-1) and the graft copolymer (A-2) is preferably 40 wt% or less, more preferably 10 to 40 wt%, and even more preferably 25 to 40 wt%. Within this range, the fluidity and weather resistance can be maintained above a certain level, and the appearance of flow marks can be suppressed, thereby improving the appearance. (B) Heat-resistant resin having a weight average molecular weight of 50,000 to 150,000 g/mol

For example, the heat-resistant resin (B) may have a weight average molecular weight of preferably 50,000 to 150,000 g/mol, more preferably 70,000 to 140,000 g/mol, and even more preferably 90,000 to 130,000 g/mol. Within this range, heat resistance may be excellent.

In the present disclosure, the weight average molecular weight can be measured by gel permeation chromatography (GPC, Waters Breeze) using tetrahydrofuran (THF) as an eluent. In this case, the relative value to a polystyrene (PS) standard sample is obtained as the weight average molecular weight. The specific measurement conditions were as follows: solvent: THF, column temperature: 40°C, flow rate: 0.3 ml/min, sample concentration: 20 mg/ml, injection volume: 5 µl, column model: 1×PLgel 10 µm MiniMix-B (250×4.6 mm)+1×PLgel 10 µm MiniMix-B (250×4.6 mm)+1×PLgel 10 µm MiniMix-B Guard (50×4.6 mm), equipment name: Agilent 1200 series system, refractive index detector: Agilent G1362 RID, RI temperature: 35°C, data processing: Agilent ChemStation S/W, and test method (Mn, Mw and PDI): OECD TG 118.

For example, based on the total weight of the base resin, the content of the heat-resistant resin (B) can be 35 to 60% by weight, preferably 35 to 55% by weight, and more preferably 38 to 52% by weight. Within this range, impact resistance, heat resistance, and hardness can be maintained at a certain level. In addition, due to excellent fluidity and die expansion ratio, flow marks can be suppressed and the appearance can be improved.

In the present disclosure, polymers generally referred to as heat-resistant resins in the field related to the present invention can be used as the heat-resistant resin of the present invention without particular limitation. Specifically, the heat-resistant resin can refer to monomers having a glass transition temperature (based on the polymer) higher than that of styrene monomers, that is, polymers containing heat-resistant monomers.

For example, the heat-resistant resin (B) may include one or more monomers selected from the group consisting of α-methylstyrene monomers and succinimidyl monomers, preferably α-methylstyrene monomers as the heat-resistant monomer. In this case, the balance between heat resistance and physical properties can be excellent.

For example, the cis-butylenediamide monomer may include one or more selected from the group consisting of cis-butylenediamide and its derivatives, preferably one or more selected from the group consisting of cis-butylenediamide, N-methyl cis-butylenediamide, N-ethyl cis-butylenediamide, N-propyl cis-butylenediamide, N-isopropyl cis-butylenediamide, N-butyl cis-butylenediamide, N-isobutyl cis-butylenediamide, N-tertiary butyl cis-butylenediamide, N-lauryl cis-butylenediamide, N- ... Citric acid imide, N-cyclohexyl citric acid imide, N-phenyl citric acid imide, N-(4-chlorophenyl) citric acid imide, 2-methyl-N-phenyl citric acid imide, N-(4-bromophenyl) citric acid imide, N-(4-nitrophenyl) citric acid imide, N-(4-hydroxyphenyl) citric acid imide, N-(4-methoxyphenyl) citric acid imide, N-(4-carboxyphenyl) citric acid imide, and N-benzyl citric acid imide.

For example, the α-methylstyrene monomer may include one or more selected from the group consisting of α-methylstyrene and its derivatives. In this case, heat resistance may be excellent.

In the present disclosure, the derivative of a compound may preferably be a compound in which one or more hydrogen groups are substituted by a substituent such as an alkyl group or a halogen group having 1 to 10 carbon atoms.

The heat-resistant resin (B) may preferably contain 60 to 80% by weight of α-methylstyrene monomers and 20 to 40% by weight of vinyl cyanide compounds, and more preferably contain 65 to 75% by weight of α-methylstyrene monomers and 25 to 35% by weight of vinyl cyanide compounds. In this case, heat resistance and mechanical properties may be excellent.

As a preferred example, the heat-resistant resin (B) may be an α-methylstyrene-vinyl cyanide copolymer, and as a more preferred example, an α-methylstyrene-acrylonitrile copolymer. In this case, heat resistance may be excellent, and excellent appearance may be achieved by suppressing the occurrence of flow marks.

The heat-resistant resin (B) may have a glass transition temperature of preferably 110 to 150° C., more preferably 110 to 140° C. Within this range, heat resistance may be excellent.

In the present disclosure, the glass transition temperature (Tg) can be measured according to ASTM D3418 using a differential scanning calorimeter (DSC, Q100, TA Instrument Co.) at a heating rate of 10°C/min.

For example, the heat-resistant resin (B) can be prepared by solution polymerization or bulk polymerization. In this case, heat resistance and fluidity can be excellent.

The present invention can use solution polymerization and bulk polymerization methods commonly used in the field related to the present invention without particular limitation. (C) Aromatic vinyl compound-vinyl cyanide compound copolymer having a weight average molecular weight of 50,000 to 70,000 g/mol

The copolymer (C) may have a weight average molecular weight of preferably 50,000 to 70,000 g/mol, more preferably 55,000 to 70,000,000 g/mol, and even more preferably 55,000 to 65,000 g/mol. Within this range, excellent appearance can be achieved by suppressing the occurrence of flow marks. When the weight average molecular weight exceeds this range, as shown in the following Comparative Example 7, processability deteriorates due to a decrease in melt index.

For example, based on the total weight of the base resin, the content of the copolymer (C) may be 6 to 25 wt%, preferably 6 to 22 wt%, and more preferably 8 to 22 wt%. Within this range, impact resistance, heat resistance, and hardness can be maintained at a certain level. In addition, due to excellent fluidity and die expansion ratio, flow marks can be suppressed and the appearance can be improved.

For example, the copolymer (C) may contain an aromatic vinyl compound and a vinyl cyanide compound. In this case, the impact resistance may be excellent, and the occurrence of flow marks may be suppressed.

As a preferred example, the aromatic vinyl compound-vinyl cyanide compound copolymer may contain preferably 50 to 90 wt % of the aromatic vinyl compound and 10 to 50 wt % of the vinyl cyanide compound, more preferably 60 to 80 wt % of the aromatic vinyl compound and 20 to 40 wt % of the vinyl cyanide compound, and still more preferably 70 to 75 wt % of the aromatic vinyl compound and 25 to 30 wt % of the vinyl cyanide compound. In this case, the flow mark can be suppressed due to the excellent fluidity and die expansion ratio.

The types of the aromatic vinyl compound and the vinyl cyanide compound contained in the copolymer (C) may be the same as the types of the aromatic vinyl compound and the vinyl cyanide compound contained in the graft copolymer (A-1) of the present invention.

For example, the copolymer (C) can be prepared by suspension polymerization, emulsion polymerization, solution polymerization, or bulk polymerization. In this case, heat resistance and fluidity can be excellent.

In the present invention, suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization methods commonly used in the field of the present invention can be used without particular limitation.

In the present disclosure, it is preferred to exclude the use of methacrylate-aromatic vinyl compound-vinyl cyanide compound copolymers other than copolymer (C). In this case, fluidity and weather resistance can be fully achieved, and flow marks can be avoided from being formed on the surface of the ejected product. However, the present invention is not limited thereto. (D) Aromatic vinyl compound-vinyl cyanide compound copolymer having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol

The copolymer (D) may have a weight average molecular weight of preferably 3,000,000 to 80,000,000 g/mol, more preferably 4,000,000 to 70,000,000 g/mol, and even more preferably 4,000,000 to 50,000,000 g/mol. Within this range, excellent appearance can be achieved by suppressing the occurrence of flow marks.

For example, based on 100 parts by weight of the base resin, the content of the copolymer (D) may be 0.5 to 4 parts by weight, preferably 0.7 to 3.7 parts by weight, more preferably 0.9 to 3.5 parts by weight, even more preferably 0.9 to 3.2 parts by weight, and even more preferably 1 to 3 parts by weight. Within this range, the fluidity may be excellent, and an excellent appearance may be achieved by suppressing the occurrence of flow marks.

For example, the copolymer (D) may be a crosslinked aromatic vinyl compound-vinyl cyanide compound copolymer. In this case, the impact resistance may be excellent, and the occurrence of flow marks may be suppressed.

For example, the crosslinked aromatic vinyl compound-vinyl cyanide compound copolymer may include one or more polyfunctional compounds selected from the group consisting of a polyfunctional thiol compound and a polyfunctional acrylic monomer in a mixture containing an aromatic vinyl compound and a vinyl cyanide compound. In this case, the impact resistance may be excellent, and the occurrence of flow marks may be suppressed.

As a preferred example, the crosslinked aromatic vinyl compound-cyanide vinyl compound copolymer is based on 100 parts by weight of a mixture containing 50 to 90% by weight of an aromatic vinyl compound and 10 to 50% by weight of a cyanide vinyl compound, and may contain 0.01 to 5 parts by weight of a multifunctional thiol compound and 0.005 to 5 parts by weight of a multifunctional acrylic monomer; more preferably, 100 parts by weight of a mixture containing 60 to 80% by weight of an aromatic vinyl compound and 20 to 30% by weight of an acrylic monomer. The present invention can include 0.5 to 3 parts by weight of a multifunctional thiol compound and 0.05 to 3 parts by weight of a multifunctional acrylic monomer based on a mixture containing 40% by weight of a vinyl cyanide compound; more preferably, 0.5 to 3 parts by weight of a multifunctional thiol compound and 0.05 to 3 parts by weight of a multifunctional acrylic monomer based on a mixture containing 70 to 75% by weight of an aromatic vinyl compound and 20 to 30% by weight of a vinyl cyanide compound per 100 parts by weight. In this case, the flow mark can be suppressed due to the excellent fluidity and die expansion ratio.

As another preferred example, the copolymer (D) may contain 0.01 to 5 parts by weight of a multifunctional thiol compound based on 100 parts by weight of a mixture containing 50 to 90 parts by weight of an aromatic vinyl compound and 10 to 50 parts by weight of a vinyl cyanide compound. In this case, the flow mark can be suppressed due to the excellent fluidity and die expansion ratio.

As another preferred example, the copolymer (D) may contain 0.005 to 5 parts by weight of a multifunctional acrylic monomer based on 100 parts by weight of a mixture containing 50 to 90 parts by weight of an aromatic vinyl compound and 10 to 50 parts by weight of a vinyl cyanide compound. In this case, the flow mark can be suppressed due to the excellent fluidity and die expansion ratio.

The types of the aromatic vinyl compound and the vinyl cyanide compound contained in the copolymer (D) may be the same as the types of the aromatic vinyl compound and the vinyl cyanide compound contained in the graft copolymer (A-1) of the present invention.

For example, the multifunctional thiol compound may include one or more selected from the group consisting of trimethylpropane tris(3-butylpropionate), trimethylpropane tris(3-butyl acetate), trimethylpropane tris(4-mercaptobutanate), trimethylpropane tris(5-butyl valerate), trimethylpropane tris(6-butyl hexanoate), pentaerythril tetrakis(2-butyl acetate), pentaerythril tetrakis(3-butyl propionate), pentaerythril tetrakis(4-butyl butyrate), pentaerythril tetrakis(5-butyl valerate), and pentaerythril tetrakis(6-mercaptohexanate).

For example, the multifunctional acrylic monomer may include one or more selected from the group consisting of ethylene dimethacrylate, diethylene glycol methacrylate, trimethylenepropane trimethacrylate, 1,3-butanediol methacrylate, 1,6-hexanediol dimethacrylate, and allyl acrylate.

The copolymer (D) can be prepared by emulsion polymerization, bulk polymerization, or suspension polymerization, preferably emulsion polymerization. In this case, an ultra-high molecular weight resin can be uniformly prepared. Thermoplastic resin composition

For example, in the thermoplastic resin composition, when the weights of (A-1), (A-2), (B), and (C) are a, b, c, and d, respectively, a, b, c, and d may satisfy the following equation 1. In this case, the flow mark may be suppressed due to the excellent fluidity and die expansion ratio. [Equation 1] a≤d＜b≤c Here, a may be an integer of 5 to 20, an integer of 7 to 20, an integer of 7 to 15, or an integer of 7 to 12. Here, b may be an integer of 26 to 35, an integer of 28 to 35, an integer of 26 to 32, or an integer of 28 to 32. Here, c may be an integer of 35 to 60, an integer of 35 to 55, an integer of 38 to 55, or an integer of 38 to 52. Here, d can be an integer from 6 to 25, an integer from 8 to 25, an integer from 6 to 20, an integer from 8 to 20, or an integer from 8 to 15.

As a specific example, the thermoplastic resin composition may satisfy the following equation 1-1. In this case, an excellent balance of physical properties may be achieved, and an excellent appearance may be achieved by preventing flow marks from occurring. [Equation 1-1] a＜d＜b＜c Here, a may be an integer from 5 to 20, an integer from 7 to 20, an integer from 7 to 15, or an integer from 7 to 12. Here, b may be an integer from 26 to 35, an integer from 28 to 35, an integer from 26 to 32, or an integer from 28 to 32. Here, c may be an integer from 35 to 60, an integer from 35 to 55, an integer from 38 to 55, or an integer from 38 to 52. Here, d can be an integer from 6 to 25, an integer from 8 to 25, an integer from 6 to 20, an integer from 8 to 20, or an integer from 8 to 15.

For example, in a thermoplastic resin composition, when the weights of (A-1), (A-2), (B), and (C) are a, b, c, and d, respectively, a, b, c, and d may satisfy the following equation 2. In this case, the flow mark may be suppressed due to the excellent fluidity and die expansion ratio. [Equation 2] 0.3≤[(a+b)/(c+d)]＜0.8 Here, a may be an integer from 5 to 20, an integer from 7 to 20, an integer from 7 to 15, or an integer from 7 to 12. Here, b may be an integer from 26 to 35, an integer from 28 to 35, an integer from 26 to 32, or an integer from 28 to 32. Here, c can be an integer from 35 to 60, an integer from 35 to 55, an integer from 38 to 55, or an integer from 38 to 52. Here, d can be an integer from 6 to 25, an integer from 8 to 25, an integer from 6 to 20, an integer from 8 to 20, or an integer from 8 to 15.

As a specific example, the thermoplastic resin composition may satisfy the following equation 2-1. In this case, an excellent balance of physical properties may be achieved, and an excellent appearance may be achieved by preventing flow marks from occurring. [Equation 2-1] 0.3≤[(a+b)/(c+d)]≤0.75 Here, a may be an integer from 5 to 20, an integer from 7 to 20, an integer from 7 to 15, or an integer from 7 to 12. Here, b may be an integer from 26 to 35, an integer from 28 to 35, an integer from 26 to 32, or an integer from 28 to 32. Here, c may be an integer from 35 to 60, an integer from 35 to 55, an integer from 38 to 55, or an integer from 38 to 52. Here, d can be an integer from 6 to 25, an integer from 8 to 25, an integer from 6 to 20, an integer from 8 to 20, or an integer from 8 to 15.

As a preferred example, the thermoplastic resin composition may satisfy the following equation 2-2. In this case, an excellent balance of physical properties may be achieved, and an excellent appearance may be achieved by preventing flow marks from occurring. [Equation 2-2] 0.3≤[(a+b)/(c+d)]≤0.7 Here, a may be an integer from 5 to 20, an integer from 7 to 20, an integer from 7 to 15, or an integer from 7 to 12. Here, b may be an integer from 26 to 35, an integer from 28 to 35, an integer from 26 to 32, or an integer from 28 to 32. Here, c may be an integer from 35 to 60, an integer from 35 to 55, an integer from 38 to 55, or an integer from 38 to 52. Here, d can be an integer from 6 to 25, an integer from 8 to 25, an integer from 6 to 20, an integer from 8 to 20, or an integer from 8 to 15.

When the thermoplastic resin composition of the present invention satisfies both equations 1 and 2, the thermoplastic resin composition can have flowability and weather resistance equivalent to or similar to that of the conventional ASA resin composition. In addition, due to the excellent die expansion ratio, the occurrence of flow marks can be suppressed.

When the thermoplastic resin composition of the present invention satisfies the following equation 3, the thermoplastic resin composition can have flowability and weather resistance equivalent to or similar to that of the conventional ASA resin composition. In addition, due to the excellent die expansion ratio, the occurrence of flow marks can be suppressed. [Equation 3] 380≤melt flow index×die expansion ratio×spiral×content of processing aid≤1,400, In equation 3, the melt flow index is a value measured at 220°C for a thermoplastic resin composition under a load of 10 kg (unit: g/10 min), the die expansion ratio is a value calculated by the following equation 4, the spiral is the length of a sample obtained by injection using a spiral mold (2.0T) and an injection molding machine (Victory 80, Engel Co.) at a pressure of 500 Kgf, an injection temperature of 300°C and a mold temperature of 80°C (unit: cm), and the content of the processing aid is the amount of the copolymer (D) (parts by weight) based on a total of 100 parts by weight of the base resin and the aromatic vinyl compound-vinyl cyanide compound copolymer. [Equation 4] Die expansion ratio = _Dex / _D0 In equation 4, _D0 is a die diameter of 2 mm, and _Dex is the diameter (unit: mm) of a sample obtained by extruding at 220°C under a load of 10 kg using a melt index tester (MI) having a die diameter ( _D0 ) of 2 mm. Equation 3 preferably satisfies the range of 400 to 1,300. In this case, flowability and weather resistance can be excellent, the occurrence of flow marks can be suppressed, and excellent appearance can be achieved. For example, when the diameter (D _ex ) of a sample obtained by extrusion at 220° C. under a weight of 10 kg is measured using a melt index tester (MI) having a die diameter (D ₀ ) of 2 mm, and the die expansion ratio is calculated by Equation 4, the thermoplastic resin composition may have a die expansion ratio of 1.3 to 1.57, preferably 1.3 to 1.55, and more preferably 1.3 to 1.54. Within this range, impact resistance and flowability may be excellent, the occurrence of flow marks may be suppressed, and excellent appearance may be achieved.

For example, when the spiral length of a sample obtained by injection at a pressure of 500 Kgf, an injection temperature of 300°C and a mold temperature of 80°C is measured using a spiral mold (2.0T) and an injection molding machine (Victory 80, Engel Co.), the thermoplastic resin composition may have a spiral length of 21.1 cm or more, preferably 21.1 to 24.4 cm. Within this range, an excellent balance of physical properties can be achieved, and an excellent appearance can be achieved by preventing the occurrence of flow marks.

For example, the thermoplastic resin composition may have a melt flow index of 6.7 g/10 min or more, preferably 6.7 to 13.2 g/10 min, measured at 220° C. for 10 minutes under a 10 kg load according to ASTM D1238. Within this range, an excellent balance of physical properties can be achieved, and an excellent appearance can be achieved by preventing the occurrence of flow marks.

For example, the thermoplastic resin composition may have a Charpy impact strength of 9 kJ/m ² or more, preferably 10 kJ/m ² or more, more preferably 10 to 15 kJ/m ² , and even more preferably 10.5 to 13 kJ/m ² measured at 23° C. using a specimen having a thickness of 4 mm according to ISO 179. Within this range, an excellent balance of physical properties can be achieved, and an excellent appearance can be achieved by preventing the occurrence of flow marks.

For example, when a thermoplastic resin composition is injected at an injection temperature of 240° C., a holding pressure of 50 bar, and an injection speed of 80 mm/s to obtain a specimen having a size of 40 mm×200 mm, no flow marks appear on the surface of the specimen. In this case, the physical property balance may be excellent, and the appearance may be improved.

According to another embodiment of the present invention, the thermoplastic resin composition comprises 100 parts by weight of a base resin, wherein the base resin comprises 5 to 20 parts by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) comprising an acrylate rubber having an average particle size of 400 to 600 nm, 20 to 40 parts by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) comprising an acrylate rubber having an average particle size of 30 to 200 nm, 30 to 60 parts by weight of a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and 5 to 30 parts by weight of a polyol having a weight average molecular weight of 50,000 to 70,000 g/mol. g/mol of an aromatic vinyl compound-vinyl cyanide compound copolymer (C); and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol. In this case, the base resin may include (A-1), (A-2), (B), and (C) in a weight ratio of 1:2 to 3:4 to 5:1 to 2 ((A-1): (A-2): (B): (C)).

For example, the thermoplastic resin composition may further include one or more additives selected from the group consisting of: lubricants, antioxidants, UV stabilizers, fluorescent brighteners, chain lengtheners, pigments, dyes, antimicrobial agents, processing aids, metal deactivators, smoke suppressants, inorganic fillers, glass fibers, antifriction agents, and anti-wear agents. At this time, based on 100 parts by weight of the base resin, the content of each additive may be 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by weight, and more preferably 0.1 to 3 parts by weight. In this case, the desired physical properties can be effectively exhibited without deteriorating the inherent physical properties of the thermoplastic resin composition of the present invention. Method for preparing thermoplastic resin composition

For example, the method for preparing a thermoplastic resin composition according to the present invention comprises the steps of kneading and extruding 100 parts by weight of a base resin at 200 to 300° C. and 100 to 500 rpm, the base resin comprising 5 to 20% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) comprising an acrylate rubber having an average particle size of 400 to 600 nm, 20 to 40% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) comprising an acrylate rubber having an average particle size of 30 to 200 nm, 30 to 60% by weight of a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and 5 to 30% by weight of a polyol having a weight average molecular weight of 50,000 to 70,000 g/mol. g/mol of an aromatic vinyl compound-vinyl cyanide compound copolymer (C); and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol. In this case, fluidity and weather resistance equivalent to or better than those of conventional ASA resins can be achieved. In addition, due to the excellent die expansion ratio, the occurrence of flow marks can be suppressed and an excellent appearance can be achieved.

The method for preparing the thermoplastic resin composition shares all the technical characteristics of the above-mentioned thermoplastic resin composition. Therefore, its repeated description will be omitted.

The step of preparing pellets using an extrusion kneading machine can be preferably performed at 200 to 300°C and φ25 to 75, more preferably at 210 to 260°C and φ20 to 70. Within this range, extrusion can be performed stably and excellent kneading effect can be obtained. In this case, the temperature is the set temperature of the cylinder, and φ means the outer diameter (unit: mm).

An extrusion kneading machine commonly used in the field related to the present invention can be used without particular limitation, and preferably a twin-screw extrusion kneading machine is used. Molded object

For example, the molded article of the present invention comprises the thermoplastic resin composition of the present invention. In this case, the flowability and weather resistance equivalent to or better than those of conventional ASA resins can be achieved, and the excellent appearance can be achieved by suppressing the occurrence of flow marks.

The method for manufacturing a molded object according to the present invention comprises the step of injecting pellets of a thermoplastic resin composition at an injection temperature of 200 to 300° C., an injection pressure of 60 to 100 bar, and a holding pressure of 30 to 65 bar. In this case, an injection-molded object having high impact strength can be easily manufactured.

The injection temperature is preferably 220 to 280° C., more preferably 230 to 270° C. Within this range, injection molded objects with complex designs can be easily manufactured.

The injection pressure is preferably 70 to 90 bar, more preferably 75 to 85 bar. Within this range, injection molded objects with complex designs can be easily manufactured.

The holding pressure is preferably 35 to 60 bar, more preferably 40 to 55 bar. Within this range, injection molded objects with complex designs can be easily manufactured.

Molded parts can be used in automotive exterior materials, including side mirror housings, radiator grilles, and filters.

When describing the thermoplastic resin composition of the present invention, its preparation method, and the molded article containing the same, it should be noted that other conditions or equipment not explicitly described herein can be appropriately selected within the scope commonly practiced in the art without particular limitation.

The present invention is described in more detail below with reference to the following preferred examples. However, such examples are for illustrative purposes only and should not be considered as limiting the scope and spirit of the present invention. In addition, it is obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention, and such changes and modifications are also within the scope of the appendix claims. [Example]

The materials used in the following examples and comparative examples are as follows. * (A-1) Graft copolymer: ASA graft copolymer containing 50% by weight of an acrylic rubber having an average particle size of 300 to 600 nm, 13% by weight of acrylonitrile, and 37% by weight of styrene (Product name: D927, LG Chemical Co.) * (A-2) Graft copolymer: ASA graft copolymer containing an acrylic rubber having an average particle size of 30 to 200 nm (Product name: D100, LG Chemical Co.) * (A-3) Graft copolymer: ASA graft copolymer containing 40% by weight of an acrylic rubber having an average particle size of 300 to 600 nm, 15% by weight of acrylonitrile, and 45% by weight of styrene (Product name: D928, LG Chemical Co.) * (B) Heat-resistant resin (α-methylstyrene: 71% by weight, acrylonitrile: 29% by weight, weight average molecular weight: 80,000 to 100,000 g/mol, bulk polymerized heat-resistant SAN resin, product name: 200UH, LG Chemical Co.) * (C-1) Aromatic vinyl compound-vinyl cyanide compound copolymer (weight average molecular weight: 60,000 g/mol, suspension polymerized branched SAN resin (long-chain branched SAN), product name: EMI-200, Find Blend Co.) * (C-2) Aromatic vinyl compound-vinyl cyanide compound copolymer (weight average molecular weight: 80,000 to 120,000 g/mol, product name: S95RF, LG Chemical Co.) * (D) Ultra-high molecular weight SAN resin: a styrene-acrylonitrile copolymer containing 75% by weight of styrene and 25% by weight of acrylonitrile and having a weight average molecular weight of 2,000,000 to 5,000,000 g/mol (product name: ZB-869, Zibo Huaxing Additives Co.) Examples 1 to 3 and Comparative Examples 1 to 8

According to the contents shown in Tables 1 and 2, the components shown in Tables 1 and 2 were introduced into a twin-screw extruder, kneaded and extruded at a barrel temperature of 240°C to prepare pellets. Using the prepared pellets, the melt flow index was measured. 0.3 wt% of a lubricant and 0.3 wt% of a UV stabilizer were added as additives. Then, using an injection molding machine (Engel Co., 120MT), the pellets were ejected at an ejection temperature of 250°C to obtain a sample for measuring physical properties. [Test Example]

The properties of the specimens prepared in Examples 1 to 3 and Comparative Examples 1 to 8 were measured by the following methods, and the results are shown in Tables 1 and 2 and Figure 1. Measurement Methods * Melt Flow Index (g/10 min): The melt flow index was measured at 220°C for 10 minutes under a 10 kg load according to ASTM D1238. * Sharp Impact Strength (kJ/m ² ): The Sharp Impact Strength was measured at 23°C using a specimen having a thickness of 4 mm according to ISO 179. * Die Expansion Ratio: The diameter (D _ex ) of the specimen obtained by extrusion at 220°C under a 10 kg load using a melt index tester (MI) having a die diameter (D ₀ ) of 2 mm was measured, and the die expansion ratio was calculated by the following Equation 4. [Equation 4] Die expansion ratio = _Dex / _D0 In equation 1, _Dex is the diameter of the extruded sample (mm), and _D0 is the die diameter (mm). * Spiral (unit: cm): The length of the sample obtained by using a spiral mold (1.5T) and an injection molding machine (Victory 80, Engel Co.) at a pressure of 500 Kgf, an injection temperature of 250°C and a mold temperature of 60°C was measured. * Whether flow marks occur: A sample with a size of 40 mm × 200 mm was obtained by using an injection machine (120MT, Engel Co.) at an injection temperature of 250°C, a holding pressure of 50 bar, and an injection speed of 90 mm/s. Then, visually observe whether flow marks appear on the surface of the sample, and evaluate the degree of flow mark appearance as follows. For reference, flow marks appear as a V-shaped wavy pattern. X: No flow marks are observed on the surface. △: Fine flow marks are observed on the surface. ○: Flow marks are observed intermittently. ◎: A large number of flow marks are observed on the surface. * Flow mark parameter: When the weights of (A-1), (A-2), (B), and (C) are a, b, c, and d, respectively, determine whether the following equation 1 is satisfied. When equation 1 is satisfied, it is expressed as ○. When equation 1 is not satisfied, it is expressed as X. For reference, the mark "○" is associated with the suppression of flow mark appearance. [Equation 1] a≤d＜b≤c * Appearance quality parameter: The values calculated by the following equation 3 are shown in the following Tables 1 and 2. For reference, when the value is in the range of 380 to 1,400, the physical property balance and appearance are adjusted to be excellent. [Equation 3] 380≤melt flow index×die expansion ratio×spiral×processing aid content≤1,400,

In Tables 1 and 2, the content of each of (A-1), (A-2), (A-3), (B), (C-1), and (C-2) is expressed in weight % based on the total weight, and the content of (D) is expressed in parts by weight based on 100 parts by weight of (A-1), (A-2), (A-3), (B), (C-1), and (C-2).

As shown in Tables 1 and 2, Examples 1 to 3 according to the present invention exhibited a shapi impact strength equivalent to or higher than that of Comparative Examples 1 to 9. In addition, in the case of Examples 1 to 3, the melt flow index and the die expansion ratio were excellent, and no flow mark was observed. In addition, Examples 1 to 3 satisfied the appropriate ranges of Equations 1 and 3.

Specifically, in the case of Comparative Example 1 which does not include the SAN resin (C) and the ultra-high molecular weight SAN resin (D), the processability is poor due to the low melt flow index. In addition, the die expansion ratio and spiral length are small, a large number of flow marks are observed, and the appropriate ranges of equations 1 and 3 are not satisfied.

In addition, in the case of Comparative Examples 2 and 3 not including the ultra-high molecular weight SAN resin (D), the die expansion ratio was small. In addition, flow marks were observed intermittently or a large number of flow marks were observed depending on the amount of the SAN resin (C) used, and the appropriate range of Equation 3 was not satisfied.

In addition, in the case of Comparative Examples 4 and 5 not including the SAN resin (C), due to the low melt flow index, the processability was poor, the spiral length was slightly shortened, fine flow marks appeared or flow marks appeared intermittently depending on the amount of the ultra-high molecular weight SAN resin (D) used, and the appropriate ranges of Equations 1 and 3 were not satisfied.

Furthermore, in the case of Comparative Example 6 including the SAN resin (C) having a molecular weight outside the appropriate range, flow marks occurred due to the low die expansion ratio, and the appropriate range of Equation 3 was not satisfied.

In addition, in the case of Comparative Example 7 including the graft copolymer (A) having a rubber having a diameter greater than the small diameter, the die expansion ratio was reduced and the spiral length exceeded 24.4 cm, resulting in poor injection moldability. In addition, the appropriate range of Equation 3 was not satisfied.

In addition, in the case of Comparative Example 8 including an excessive amount of ultra-high molecular weight SAN resin (D), the spiral length was shortened and did not satisfy the appropriate range of Equation 3.

FIG1 below shows whether flow marks appear on the samples of Example 1 and Comparative Examples 1, 3, and 5. As shown in FIG1 , no flow marks were observed on the sample of Example 1, indicating that the sample of Example 1 has an excellent appearance.

On the contrary, in the case of Comparative Examples 1, 3, and 5, a large number of wavy flow marks were observed on the samples, indicating that the samples of Comparative Examples 1, 3, and 5 had a poor appearance.

In summary, by adjusting the die expansion ratio of the five-component thermoplastic resin composition including a graft copolymer containing acrylic rubber with different average particle sizes, a heat-resistant resin, and a thermoplastic copolymer with different molecular weight ranges, excellent fluidity and weather resistance can be obtained due to the synergistic effect of these components. In addition, the appearance of flow marks can be suppressed, thereby improving the appearance quality. Therefore, the thermoplastic resin composition of the present invention can be used to manufacture exterior materials with excellent reliability.

[FIG. 1] includes images taken to observe the appearance of flow marks on the surface of the injection specimens having a size of 40 mm×200 mm prepared in Example 1 and Comparative Examples 1, 3, and 5.

Claims (15)

A thermoplastic resin composition comprising: 100 parts by weight of a base resin comprising an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) containing an acrylate rubber having an average particle size of 400 to 600 nm, an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) containing an acrylate rubber having an average particle size of 30 to 200 nm, a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and an aromatic vinyl compound-vinyl cyanide compound copolymer (C) having a weight average molecular weight of 50,000 to 70,000 g/mol; and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol. The thermoplastic resin composition of claim 1, wherein when the weights of (A-1), (A-2), (B), and (C) are a, b, c, and d, respectively, a, b, c, and d satisfy the following equation 1: [Equation 1] a≤d＜b≤c, wherein a is an integer from 5 to 20, b is an integer from 26 to 40, c is an integer from 30 to 60, and d is an integer from 6 to 25. The thermoplastic resin composition of claim 1, wherein the base resin comprises (A-1), (A-2), (B), and (C) in a weight ratio of 1:2 to 3:4 to 5:1 to 2 ((A-1): (A-2): (B): (C)). The thermoplastic resin composition of claim 1, wherein the aromatic vinyl compound-vinyl cyanide compound copolymer (D) has an intrinsic viscosity (IV, 25°C) of 10 dL/g or more, a bulk density of 0.1 to 0.5 g/ ^cm3 , and a weight average molecular weight greater than 1,000,000 g/mol. The thermoplastic resin composition of claim 4, wherein the aromatic vinyl compound-vinyl cyanide compound copolymer (D) is a copolymer containing 50 to 90 wt % of an aromatic vinyl compound and 10 to 50 wt % of a vinyl cyanide compound. The thermoplastic resin composition of claim 1, wherein the total amount of (A-1) and (A-2) is 40 wt% or less, based on 100 wt% of all components constituting the base resin. The thermoplastic resin composition of claim 1, wherein the heat-resistant resin (B) comprises 60 to 80 wt % of α-methylstyrene monomers and 20 to 40 wt % of vinyl cyanide compounds. A thermoplastic resin composition as claimed in claim 1, wherein, based on 100 wt % of the acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1), the acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) comprises 40 to 60 wt % of an acrylate rubber, 25 to 45 wt % of an aromatic vinyl compound, and 5 to 20 wt % of a vinyl cyanide compound. A thermoplastic resin composition as claimed in claim 1, wherein, based on 100 wt % of the total acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2), the acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) comprises 40 to 60 wt % of acrylate rubber, 25 to 45 wt % of aromatic vinyl compound, and 5 to 20 wt % of vinyl cyanide compound. The thermoplastic resin composition of claim 1, wherein the aromatic vinyl compound-vinyl cyanide compound copolymer (C) contains 50 to 90 wt % of the aromatic vinyl compound and 10 to 50 wt % of the vinyl cyanide compound. A thermoplastic resin composition comprising: 100 parts by weight of a base resin comprising 5 to 20% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide graft copolymer (A-1) comprising an acrylate rubber having an average particle size of 400 to 600 nm, 20 to 40% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide graft copolymer (A-2) comprising an acrylate rubber having an average particle size of 30 to 200 nm, 30 to 60% by weight of a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and 5 to 30% by weight of an aromatic vinyl compound-vinyl cyanide copolymer (C) having a weight average molecular weight of 50,000 to 70,000 g/mol; and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol, wherein the base resin comprises (A-1), (A-2), (B), and (C) in a weight ratio of 1:2 to 3:4 to 5:1 to 2 ((A-1): (A-2): (B): (C)). The thermoplastic resin composition of claim 1 or 11, wherein the thermoplastic resin composition satisfies the following equation 3: [Equation 3] 380≤melt flow index×die expansion ratio×spiral×content of processing aid≤1,400, wherein the melt flow index is a value measured for the thermoplastic resin composition at 220°C under a load of 10 kg according to ASTM D1238 (unit: g/10 min), the die expansion ratio is a value calculated by the following equation 4, and the spiral is a value obtained by using a spiral mold (2.0T) and an injection molding machine (Victory 80, Engel Co.) at 500°C. The length of the sample obtained by injection at an injection temperature of 300°C and a mold temperature of 80°C under a pressure of 100 kgf (unit: cm), and the content of the processing aid is the amount of the copolymer (D) (parts by weight) based on a total of 100 parts by weight of the base resin and the aromatic vinyl compound-vinyl cyanide compound copolymer. [Equation 4] Die expansion ratio = _Dex / _D0 , wherein _D0 is a die diameter of 2 mm, and _Dex is a diameter of a sample obtained by extruding at 220°C under a load of 10 kg using a melt indexer (MI) having a die diameter ( _D0 ) of 2 mm (unit: mm). The thermoplastic resin composition of claim 12, wherein Equation 3 satisfies the range of 400 to 1,300, the melt flow index is 6.7 to 13.2 g/10 min, the die expansion ratio is 1.31 to 1.54, and the spiral is 21.1 to 24.4 cm. A method for preparing a thermoplastic resin composition, comprising kneading and extruding 100 parts by weight of a base resin at 200 to 300° C. and 100 to 500 rpm, the base resin comprising 5 to 20% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-1) comprising an acrylate rubber having an average particle size of 400 to 600 nm, 20 to 40% by weight of an acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A-2) comprising an acrylate rubber having an average particle size of 30 to 200 nm, 30 to 60% by weight of a heat-resistant resin (B) having a weight average molecular weight of 50,000 to 150,000 g/mol, and 5 to 30% by weight of a polyol having a weight average molecular weight of 50,000 to 70,000 g/mol. g/mol of an aromatic vinyl compound-vinyl cyanide compound copolymer (C); and 0.5 to 4 parts by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer (D) having a weight average molecular weight of 1,000,000 to 10,000,000 g/mol, wherein the base resin comprises (A-1), (A-2), (B), and (C) in a weight ratio of 1:2 to 3:4 to 5:1 to 2 ((A-1): (A-2): (B): (C)). A molded article comprising the thermoplastic resin composition of claim 1 or 11.